The present invention relates to gauging and bending or aligning apparatus. The gauging and bending apparatus is particularly contemplated for use in aligning radially arranged airfoil elements such as guide vanes or turbine blades in turbojet engines. In this connection, reference is made to prior U.S. Pat. No. 3,464,119, issued Sept. 2, 1969 to the inventor of the present gauging and bending apparatus. That patent relates to a classification gauge suitable for determining the relative effective open area in various stages of the turbojet engines.
Substantial background information is set forth by the above noted patent and is not included herein since it is not believed essential to an understanding of the present invention. Generally, it is believed sufficient to understand that a precisely determined, effective open area between adjacent guide vanes, commonly referred to as "throat area," is necessary to permit proper passage of gases through various stages of such engines. The throat area of a turbojet engine must be closely regulated in order to allow the engine to perform properly. If the throat area is below a minimum amount, "choke-off" may occur and the desired quantity of fluid or gas may not be able to pass through that engine stage.
The classification gauge referred to above is suitable for determining the proper classification of individual guide vanes used in various stages of such engines. The classification gauge functions generally to accurately position a trailing edge of the airfoil within a precision jig and then to arrange a spaced-apart portion of the airfoil in a position determined by other parameters including the effective total length for the guide vane. The guide vane may thus be accurately positioned in an angular arrangement with an indicating gauge then being effective to measure the relative angular position of a mounting flange for the guide vane in order to closely determine the existing open throat area for one or more guide vanes or airfoil elements. However, such a classification gauge could not be used to vary the effective throat area for an existing array of airfoil elements or vanes.
Accordingly, there remains a need for apparatus to gauge or determine the effective classification for vane clusters or individual airfoil elements as well as to adjust the angular alignment of the vanes or elements at a preselected value as part of the same operation. Apparatus for accomplishing these combined functions of gauging and bending could be adapted for use in a variety of other applications as well.